It depends on how quickly you get off the boat.
If you skip breakfast, don't have anything to declare, and get off the ship as fast as the all clear appears, you may be to the airport as early as 9:00. But that does assume NOTHING goes wrong in the ship getting its all clear.
We had main dinner seating and ate breakfast (which meant breakfast at 6:45). We would have been through customs by 8:30, but had some lost luggage. We were still at the airport by 10:00.
If you have late breakfast, take your time getting off the ship, or have problems with luggage or customs, its possible you won't get to the airport until 11:00 or later.
Note that the line for security checkpoints at MCO can get quite long - when we got to the airport it was 45 minutes to get through security.